/Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Public/ViewModels/NiagaraSystemViewModel.h
Add a serialized message to the target function call node inside a script this viewmodel is managing. Returns a key to the new message.
[FGuid](API\Runtime\Core\Misc\FGuid) AddStackMessage ( [UNiagaraMessageData](API\Plugins\NiagaraEditor\UNiagaraMessageData) * NewMessage, [UNiagaraNodeFunctionCall](API\Plugins\NiagaraEditor\UNiagaraNodeFunctionCall) * TargetFunctionCallNode ) const